High-temperature greases



I Patented Jan. 29, 1946 HIGH-TEMPERATURE GREASES John D.Morgan,"Southrange, N. J., assignor to Cities Service Oil Company, NewYork, N. Y., a corporation of Pennsylvania No Drawing. Application April28, 1943, Serial No. 484,861

9 Claims. (or. 252-36) This invention relates to improvements in reasesfor high temperature use, and more particularly to such greasescontaining large proportions of petrolatum,

A variety of petrolatums have been used in the manufacture oflubricating greases, but as far as known they have constitutedrelatively minor proportions of the grease. In the manufacture ofgreases suitable for high temperature use or greases having a relativelylow penetration, it has almost invariably been necessary to employ highpercentages of soaps. For example, it appears from published data that asoap content of from 25% to 30% is necessary in order to provide agrease with a penetration of about 140. Only about half that amount ofsoap is used in the greases of this invention. l

In accordance with the present invention, it has been discovered that anexcellent high temperature grease may be made from a moderate proportionof lithium stearate in petrolatum. This was an unexpected result becauseprevious work had shown that a grease could not be made fromPennsylvania type oils and lithium stearate alone. A similar diflicultyhad been previously experienced in attempts to make greases from sodiumsoaps and Pennsylvania oils, which are classed as oils of low polarit(Klemgard Lubricating Greases, 1937, pages 362 to 363). Petrolatums areregarded as extremely nonpolar, but excellent dispersions of lithiumsoap inv petrolatum have been secured by the practice of the presentinvention.

The manufacture of greases in accordance with this invention'maybeillustrated by reference to the following example in which thequantities of the various ingredients are given in percentages byweight.

A grease having a penetration of140 (worked A. S. T. M.) was prepared bymelting and intimately mixing 11% by weight of lithium stearate, 2.2% byweight of aluminum stearate, 0.5% by weight of tributyl phosphite and76.3% by weight of green petrolatum. The tributyl phosphiteis used as anantioxidant. This grease in addition to having the penetrationindicated, had-a dropping point of 370 F. The grease furthermore stoodtheseven-hour test in the Navy beater testing apparatus in which abearing, is rotated under forced circulation at 3600 revolutions perminute while the grease is heated to a temperalatum grease was free ofglycerine, and in fact a substantially pure product made from lithumcarbonate and stearic acid. The petrolatum used may be refined insteadof the crude product.

ture of 350 F. At the end of this test the grease I was still in goodcondition and was superior to v knowncommercial greases,

The lithium stearate used in making the petro- The more refined andwhiter the petrolatum, the lighter color is the resulting grease.Greases made in accordance with the present invention may be made fromsomewhat variable quantities of stearate or otherlithium soap andaluminum stearate or other aluminum soap, the balance of the grease ineach case consisting essentially of petrolatum. The proportion oflithium soap may vary from about 8% to 14%, while the proportion ofaluminum soap may vary from 1.5% to 4%, the higher proportions ofaluminum soap being used with the higher proportions of lithium soap.Greases made in accordance with the present, invention are preferablymade without the use of mineral or other oils.

A softer grease than the penetration grease described above may be madeby including from 1% to 4% of a lead or a silver soap, for example theoleates. The inclusion of 2% of lead oleate in the composition describedabove raises the penetration to about 240, and gives a grease whichstill has the high temperature characteristics. The use of thisadditional soap seems to give an effect different from that normallyexpected since it is generally found that the larger the proportion ofsoap, the lower the penetration of the grease. The lead or silver soapin the percentage range referred to, maybe used in the making of otherspecific greases containing different proportions of lithium soap or inmaking greases containing lithium soap and aluminum soap in the range ofproportions referred to above. The aluminum soap seems to aid indispersing the lithium soap in the petrolatum.

Antioxidants such as tributyl phosphites, are not essential to theproduction of a good grease in accordance {with the present invention,but such an antioxidant is preferably employed to aid in prolonging thelife of the grease and to inhibit oxidation and corrosion. Other knowninhibitors may be employed such as other alkyl phosphites, arylphosphites and amino compounds.

Although the features of the invention have been describedand'illustrated in accordance with certain specific examples, it is tobe understood thatithe invention is not to belimited thereto orotherwise be restricted, except by the prior art and the'scop'e oftheappended claims.

Having described the invention and illustrated 1. A hightemperaturegrease comprising approximately 11 by weight of lithium soap.2.2%-

by weight of aluminum soap, the remainder being essentially petrolatum.1 X

2. A high tempera e lubricant having an A. S. T. M. penetration of about140 and consisting essentially otirom'8% to 14% by weiaht of lithiumstearate, from 1.5% to 4% of aluminum stearate, the remainder-of thelubricant being composed essentially of petrolatum.

3. A high temperature grease consisting of petrolatum having dispersedtherein from about 8% to about 14% by weight of a lithium soap based onthe weight of the grease. v

4. A high temperature relatively hard grease consisting essentially ofpetrolatum, from 8% to about 14% by weight of a lithium soap; and from,1% to 4% by weight of a soap having a softening effect on the grease andselected from the group consisting of lead and silver soaps. A

5. A high temperature grease comprising approximately 11% by weight oflithium stearate,

ap r xim tely 22% y w ight of aluminum m ate, approximately --'0.5% byweight of an antioxidant, and approximately 76.3% by weight ofpetrolatum. 6.Agreaseasdeilnedbyclaimfiwhichineludes a, relativelysmallproportion of a soap selected from the silversoal s- 7. A lubricantconsisting of a petrolatum which is dispersed approximately 11% byweightv of a lithium soap based on the weight of the grease and a dispersionmedium comprising an aluminum soap.

group consisting of lead and

